10 x CHR-70 + 1 TH-SPUD for 5.1 HT setup?

[soren5]

Happy New Year!

My uncle and I are planning to build a HT setup for his living room. I have an idea, but would appreciate some advice before we begin.

The room is fairly large, around 5x7 meters with sloping ceilings - 2.7 meters high sidewalls and 4.7 meters to the sealing in the center. My idea is to build a 5.1 system with five channels, each with two Markaudio CHR-70.3s. The subwoofer I'm considering is a 2x8" tapped horn TH-SPUD clone.

I'd like to wall mount all five channels, but I'm not sure what would be the best design for these speakers. Sealed boxes would be easier to build and also better looking IMO (smaller). With two CHR-70.3s paralleled in a 16 liter sealed box I get 87Hz F3 according to WinISD. If I roughly double the size and make it vented I can reach 40Hz F3.

This leads me to the following questions:

1. Would you recommend sealed or vented enclosures for the five channels? Or perhaps a combination of sealed and vented boxes, e.g. vented mains and sealed center and surrounds?
   
   
2. I've read about people having phase alignment issues when mixing different enclosure types in the same system. Could this be a problem here? Tapped horn sub mixed with sealed/vented channels?
   
   
3. The TH-SPUD subwoofer has a FR of 19-125Hz on the paper, but from other build threads I hear about some severe resonant peaks in the higher frequencies, which I believe need to be filtered out. If I cut the sub at say 90Hz could I then successfully cross over to sealed channels, which have an 87Hz F3, or is that pushing it?

We are yet to buy any of the many ingredients for this setup, so please let me know if you think I'm completely off track here. I'm open to other ideas and suggestions.

By the way, I imagine the system will be powered by a 5 channel DIY class-D/T amp (probably Hypex or Hifimediy modules), and the subwoofer(s) will have it's own readymade power amp.

Thanks for the help!

[skeeter99]

I think that sounds like a great setup and I think doing sealed all around is a great idea. Crossing over around 90hz or so would be great between the two. I personally prefer 80hz but don't know really how much of an audible difference it would make going to 90hz. Nice thing is that you can always experiment to find the best for your application. Also doing identical cabinets makes building them much easier and aesthetically would look cool as well

Scott

[planet10]

Originally Posted by skeeter99

how much of an audible difference it would make going to 90hz

Not much

But with room gain from wall mounting, actual response will likly be lower than simmed.

dave

[soren5]

Originally Posted by planet10

But with room gain from wall mounting, actual response will likly be lower than simmed.

Am I understanding you correctly if this means that the actual F3 will be lower than the simmed 87Hz? And does this mean that I should make the sub's high-pass filter at a lower frequency?

If possible I'd like to run all five channels without low-pass filters, meaning that the only crossover will be in the subwoofer.

[chrisb]

Originally Posted by soren5

Am I understanding you correctly if this means that the actual F3 will be lower than the simmed 87Hz? And does this mean that I should make the sub's high-pass filter at a lower frequency?

If possible I'd like to run all five channels without low-pass filters, meaning that the only crossover will be in the subwoofer.

The DSP /bass management in most typical HT receivers (and I would have presumed HT-PC setups) allow for much higher HP filtering to the mains and surrounds than 80-90 - often with different settings for each channel. When using even multiples of full-range drivers of this "weight class", I'd be inclined to set in the 100-120Hz range and gain as much excursion headroom as possible.

[planet10]

Play. Let it auto setup and work from there.

dave

[skeeter99]

Originally Posted by planet10

Play. Let it auto setup and work from there.

dave

My thoughts exactly. There's so much manipulation that can be done with the AVR that the standard 80hz crossover point at least gives you a starting point and from there you can experiment with what works best in your room with your gear and to your ear.

Scott

[soren5]

Thanks for the comments.

This will be my first HT build so I don't know a whole lot about AV receivers. However, I'd like to keep the cost of the project as low as possible and avoid having to purchase an advanced and expensive AV receiver with 'auto setup' features.

My initial thought was to buy a cheap 5.1 decoder like this or this. Do you have recommendations for a good value surround decoder/preamp?

Another option would be to forget about the multichannel power amp project and instead spend the money on a integrated AV receiver. What are your thoughts on this?

[chrisb]

Originally Posted by soren5

Thanks for the comments.

This will be my first HT build so I don't know a whole lot about AV receivers. However, I'd like to keep the cost of the project as low as possible and avoid having to purchase an advanced and expensive AV receiver with 'auto setup' features.

My initial thought was to buy a cheap 5.1 decoder like this or this. Do you have recommendations for a good value surround decoder/preamp?

Another option would be to forget about the multichannel power amp project and instead spend the money on a integrated AV receiver. What are your thoughts on this?

Honestly, I'd go for a mainstream AV receiver - plug and play and silly good value for from under $400 to whatever you wanna spend - but note that none will include power amp for LF channel.

[Bigun]

I bought a blu-ray player with 7.1 analogue outputs and then built my own amps to go on the outputs. No receiver was needed and I still don't use one. It has been fun, potentially gives more flexibility and future upgrade options for ultimate quality, but it's a longer journey til you get something up and running and you have to do the set up manually. Unless you want all of that, I'd suggest an all-in-one solution is the way to go too.

Don't rule out a used AV receiver - may allow you to get a better quality unit.

I agree with Chris - sub should be self-powered using an off-the-shelf plate amp.